A new method of measuring two-phase mass flow rates in a venturi

Metering of the individual flow rates of gas and liquid in a multicomponent flow is of great importance for the oil industry. A convenient, nonintrusive way of measuring these is the registration and analysis of pressure drops over parts of a venturi. Commercially available venturi-based measuring equipment is costly because it also measures the void fraction. This paper presents a method to deduce the individual mass flow rates of air and water from pressure drop ratios and fluctuations in pressure drops. Not one but two pressure drops are used and not only time-averaged values of pressure drops are utilized. As a proof-of-principle, prediction results for a horizontal and vertical venturi are compared with measurements for void fractions up to 80. Residual errors are quantified and the effect of variation of equipment and of slip correlation is shown to be negligible. At relatively low cost a good predictive capacity of individual mass flow rates is obtained.